Trainer Pam Sly's Speciosa took the field along from Time On and Guilia and there was little change in the order as the fillies came round Tattenham Corner.

As the 10 runners thundered into the straight, Speciosa's challengers came on both sides but it was Alexandrova, second to Short Skirt in the Musidora Stakes at York, who flew down the outside.

She went round there as sweet as a nut and she made it easy for me

Kieren Fallon

John Best's Rising Cross tried to close the gap but she stumbled in the closing stages, though Baker held on to edge out Sir Michael Stoute's Short Skirt by a length and a quarter.

Fallon told BBC Sport: "They didn't go that quick and when that happens you can get left behind when they quicken from the front, but I got there sooner than I wanted.

"She gave me a really good feel and galloped all the way to the line - I didn't think she would have improved that much (from her first run at York).

"She never travelled after that bump when coming out of stalls at York but she went round there as sweet as a nut and she made it easy for me."

John Magnier, head of the Coolmore operation behind O'Brien, said: "Kieren tried to hold her up but had to let her go. She was very good there and today was our day.

"This bit of ground (in the winner's enclosure) is where we all want to be - this is a fantastic place.

Rising Cross is going to make a serious broodmare now but every time they keep leaving it the price keeps going up

Trainer John Best

"She has done what she was meant to do now - she was bred to win the Oaks and she has won it, so we will be careful with her from now on."

Best, who supplemented Rising Cross at a cost of £20,000, said: "I could see her coming down the hill and for a minute I could see her running a really big race and going and winning it. But even so that was just a tremendous effort.

"She is for sale and has been all along, and if someone comes along to buy her she will be gone. She is going to make a serious broodmare now but every time they keep leaving it the price keeps going up."